Epoxy vinyl ethers and synthesis of an epoxy vinyl ether from a hydroxylated vinyl ether and a polyepoxide

ABSTRACT

This invention relates to epoxy vinyl ethers having the formula: ##STR1## wherein R is a polyvalent linear, branched or cyclic hydrocarbon radical having from 2 to 20 carbon atoms, optionally substituted with alkylenoxy; n has a value of from 1 to 20; p has a value of from 1 to 6; and at least one of Y and Y&#39; is ##STR2## which any remaining Y and Y&#39; can be ##STR3## The invention also relates to the synthesis and uses of the above polyphenyl vinyl ethers.

This application is a continuation-in-part of copending U.S. patentapplication Ser. No. 424,453, filed Oct. 20, 1989 entitled EPOXY VINYLETHERS.

In one aspect the invention relates to novel polyphenyl vinyl etherswhich are rapidly curable by cationic radiation to durable protectivecoatings or films having high resistance to abrasion and chemicalattack. In another aspect the invention relates to polyphenyl vinylethers as reactive monomers in the curing of vinyl ether, epoxy oracrylate monomers or polymers. In still another aspect, the inventionrelates to a method of synthesizing the present polyphenyl vinyl ethers.

BACKGROUND OF THE INVENTION

Certain radiation curable coatings and films such as those formed fromthe acrylates, particularly propane trimethanol triacrylate,trimethacrylate, pentaerythritol triacrylate, and hexanediol diacylateor methacrylate, are in great demand because of their rapid curingproperties.

Since acrylate compounds are not conducive to cationically inducedradiation curing, they require more costly free radical systems whichare oxygen inhibited unless effected in an inert atmosphere, generallyunder a blanket of nitrogen. Although formulation with a photoinitiatorwhich undergoes bimolecular reaction with a hydrogen donor minimizes theinhibitory effect of air, this benefit is realized at the expense of agreatly reduced cure rate. Also, it is found that polymerization orcuring in free radical systems ceases almost immediately upon removalfrom the source of radiation; thus, the cured product likely containssignificant amounts of unpolymerized components. Accordingly, it is anaim of research to develop a compound having the beneficial propertiesof acrylates but which is amenable to radiation curing at a rapid rateby cationically induced polymerization which is not oxygen inhibited andwhich permits continued polymerization after removal from the source ofradiation exposure.

Finally, it is noted that the unsubstituted acrylates are sensitizersand skin irritants as well as being carcinogenic, so that specializedsafety precautions must be taken to protect operators from exposure.Although alkoxylation has lessened irritancy of the acrylates, theircarcinogenic properties are not reduced.

Accordingly, it is an object of this invention to overcome or minimizethe above described deficiencies and to provide oligomeric materialscapable of altering the curing characteristics of vinyl ether, epoxy andacrylate monomers and polymers.

Another object of this invention is to provide an economical andcommercially feasible process for synthesizing radiation curable epoxyvinyl ethers.

Still another object of this invention is to provide compounds whichpossess good photoresist properties.

Another object is to provide a homopolymerizable compound readilycurable by cationic radiation to a hard coating or film which isresistant to chemical attack.

These and other objects of the invention will become apparent from thefollowing description and disclosure.

THE INVENTION

According to this invention there is provided an epoxy vinyl etherhaving the formula ##STR4## wherein R is a polyvalent linear, branchedor cyclic hydrocarbon radical having from 2 to 20 carbon atoms,optionally substituted with alkyleneoxy; n has a value of from 1 to 20;p has a value of from 1 to 6; and at least one of Y and Y' is ##STR5##while each of any remaining Y and Y' can be ##STR6## Of the abovedefined polyphenyl vinyl ethers, those wherein R is C₂ to C₆ alkylene, nhas a value of from 1 to 12 and Y and Y' are ##STR7## are preferred.Most preferred of this group are where n and p have a value of from 1 to4.

The synthesis of the above epoxy vinyl ethers involves the reaction of ahydroxylated vinyl ether reactant, (HO)_(p) ROCH═CH₂, and a polyepoxyaryl hydroxyalkyl ether coreactant, of the formula ##STR8## wherein R, pand n are as defined.

The amounts of reactant and coreactant employed in the synthesis processto produce the epoxy polyphenyl product are critical. Specifically, thetotal number of epoxy groups, ##STR9## respect to the total amount of--OH groups in the system, must be in excess of at least one. Forexample, as an upper limit, when n is 20 and p is 1, there can be 21epoxy GROUPS/OH. In the later case, where p is 1 , only one epoxy group,of the original 22 epoxy groups, reacts. When a polyhydroxylatedreactant is employed, e.g. (HO)₃ ROCH═CH₂, and n has a positive value,e.g. 2, the ratio of reactant to coreactant is 1:1, whereby the producthas one unreacted epoxy group; however when 2 moles of the coreactant to1 mole of the reactant is employed, the product contains 5 unreactedepoxy groups. In another case where (HO)₃ ROCH═CH₂ is the reactant and nin the coreactant is 6, the ratio of reactant to coreactant can varyfrom 1:0.5, where the product contains 1 remaining epoxy group, up to1:1 where the product contains 5 remaining epoxy groups. Hence bycontrolling the amount of reactant to coreactant, or vice versa, all ofthe hydroxy groups of the hydroxylated vinyl ether will be reacted andthe product will always contain at least one epoxy group. It isessential to retain an epoxy group in the product where derivatives ofthe present products are desired.

The reaction can be carried out in the presence of air or in the absenceof oxygen under a blanket of inert gas. Generally, the presentcondensation reaction is carried out at a temperature of between about100° and about 175° C. under atmospheric pressure for a period of from0.5 to 200 hours. Preferred reaction parameters include a temperature offrom about 120° to about 160° C. for a period of from about 2 to about100 hours.

The reaction is also conducted in the presence of a base catalyst suchas particulate sodium, potassium, or lithium metal, sodium or potassiumhydroxide or hydride. The catalyst is present in an amount of from about0.01 to about 2 wt. %, preferably from about 0.1 to about 1 wt. % of thetotal mixture. When the reactants and products included herein areliquids, they are generally synthesized in the absence of diluents orsolvents which are otherwise required for more viscous or solidreactants.

Suitable hydroxylated vinyl ether reactants include the mono vinyl etherof cyclohexanetrimethanol, tetra(hydroxyethyl) vinyloxy hexane,(2-hydroxyethyl) vinyl ether, (3-hydroxypropyl) vinyl ether, themonovinyl ether of 3-ethyl-1,6-hexanediol, (4-hydroxybutyl) vinyl ether,the monovinyl ether of cyclohexanediamethanol, the monovinyl ether oftris(hydroxymethyl) ethane, the divinyl ether of2-ethyl-2-(hydroxymethyl)1,3-propanediol, the divinyl ether oftris(hydroxymethyl) ethane, the monovinyl ether of2-methyl-1,8-octanediol, (vinyloxy) cresol, (vinyloxy) xylol andalkoxylated derivatives thereof containing from 1 to 6 ethyleneoxy orpropyleneoxy units. Suitable aromatic polyepoxy reactants include theterminally substituted diepoxy compounds of propyl epoxy derivatives ofnovolac resins.

Commercially available polyepoxy reactants suitable for use in thepresent reaction include D.E.N. epoxy Novolac resins (supplied by DowChemical Company) and the like. These epoxy reactants are readilyprepared by well known procedures, such as the procedure outlined onpages 10 through 21 of Chapter 2 of HANDBOOK OF EPOXY RESINS by HenryLee and Kris Neville, published by McGraw Hill Book Company, 1967.

The products of this invention can be homopolymerized to hard chemicallyresistant films and coatings which have good substrate substantivity.Alternatively, the present compounds, particularly the polyepoxideproducts, can be mixed with alkenyl ether, alkenyl ester, epoxide oracrylate monomers or polymers to impart rapid radiation curingproperties in the presence of a cationic photoinitiator. Cross-linkingcopolymerizations can be carried out in the presence of air to producehighly desirable films and coatings which retain the desirableproperties of both monomers or their polymerized derivatives. Curablecompositions containing between about 0 and about 80% of a vinyl ether,an epoxide, an acrylate or a methacrylate comonomer or a polymer thereofand between about 20% and about 100% of the present epoxy vinyl ether inthe presence of from about 0.05 to about 5 wt. % of a photoinitiator aresuitable radiation curable coatings which are polymerized by exposure toUV light, electron beam, lazer emission or other source of radiation.Between about 2 and about 50 wt. % of the present product with fromabout 0.1 to about 5 wt. % of a conventional cationic photoinitiator,such as an onium salt including the triphenyl sulfonium salt ofphosphorous hexafluoride, diphenyl iodium salt, tetrazolium chloride,phenyl onium salts or aryl alkyl onium salts cationic initiators and/orfree radical initiators such as 1-hydrocyclohexyl phenyl ketone (e.g.IRGACURE 184), 2-hydroxy-2-methyl-1-phenyl-1- propane-1-one (DAROCUR1173), 2,2-dichloro-1-(4-phenoxyphenyl) ethanone (SANDORAY 1000) andother free radical and cationic initiators which are suitably employedin this invention, as described by M.J.M. Abadie, Advantages andDevelopment of Photochemical Initiators, in the European CoatingsJournal 5/1988 pages 350-358, can be admixed With an acrylic compoundnormally not conducive to rapid cationic radiation curing, such as anacrylate or methacrylate comonomer, to effect curing within a fewseconds exposure to a source of radiation. These coatings are applied toa substrate such as glass, ceramic, wood, plastic, metal and the like inthicknesses of from about 0.1 to about 5 mils. Additionally, thecompounds of this invention, because of their sensitivity topolymerization by radiation, find application as photoresist materials.

Curing of the present compounds or their admixtures with comonomers canbe effected in less than 1 second by exposure to between about 100 andabout 800 millijoules/cm² of UV light, between about 0.5 and about 5megarads of electron beam exposure or equivalent radiation exposures.

Having generally described the invention reference is now had to theaccompanying examples which illustrate preferred embodiments which arenot to be construed as limiting to the scope of the invention morebroadly defined above and in the appended claims.

EXAMPLE 1

D.E.N. 438 Epoxy Novolac Resin (1095 g.), 4-hydroxybutyl vinyl ether(446.5 g.) and potassium hydroxide 1.0 g. were charged into a 2-literflask equipped with a mechanical stirrer, nitrogen inlet, thermometer, acondenser and a drying tube. The solution was heated at 150° C. for 72hours under a blanket of nitrogen. Greater than 90% conversion to agel-like product comprising ##STR10## was obtained.

EXAMPLE 2

D.E.N. 439 Epoxy Novolac Resin (1231.2 g.), the monovinyl ether oftriethylene glycol (352.3 g.) and 3 g. of potassium hydroxide arecharged into a 2-liter flask. The solution is heated at 120° C. for 24hours and then at 150° C. for 72 hours. Greater than 90% conversion to agel-like product comprising ##STR11## was obtained.

What is claimed is:
 1. The compound having the formula ##STR12## whereinR is a polyvalent linear, branched or cyclic hydrocarbon or alkoxylatedhydrocarbon radical having from 2 to 20 carbon atoms, n has a value offrom 1 to 20; p has a value of from 1 to 6 and at least one of Y and Y'is ##STR13## while any remaining Y and Y' can be ##STR14##
 2. Thecompound of claim 1 wherein R is a C₂ to C₆ aliphatic hydrocarbon, n hasa value of from 1 to 12 and Y is ##STR15##
 3. The compound of claim 2wherein R is a C₂ to C₆ aliphatic hydrocarbon, n has a value of from 1to 12 and Y and Y' are each ##STR16##
 4. The compound ##STR17##
 5. Thecompound ##STR18##
 6. The process for synthesizing the compound of claim1 which comprises contacting a hydroxylated vinyl ether reactant of theformula

    (HO).sub.p ROCH═CH.sub.2

and a polyepoxy aryl hydroxyalkyl ether coreactant of the formula##STR19## wherein R, p and n are as defined and wherein the total numberof epoxy groups with respect to the total number of hydroxy groups inthe reaction system is in excess of at least one and reacting saidreactant and coreactant at a temperature of from about 100° C. to 175°C. in the presence of from about 0.01 to about 2 wt. % of a basecatalyst.
 7. The process of claim 6 wherein the number of epoxy groupswith respect to the number of hydroxy groups in the reaction system isin excess of from 1 to
 21. 8. The process of claim 6 wherein saidhydroxylated vinyl ether is

    CH.sub.2 ═CHOC.sub.4 H.sub.8 OH.


9. The process of claim 6 wherein said hydroxylated vinyl ether is themonovinyl ether of cyclohexane dimethanol.
 10. The process of claim 6wherein said hydroxylated vinyl ether is the monovinyl ether oftriethylene glycol.
 11. The process of claim 6 wherein n has a value offrom 1 to 4.